The Irish singer is expecting her second baby with husband Ben but kept any hint of a bump well covered under her cute stage costumes.
In two new pictures, Una can be seen getting her grove on and singing her heart out while performing on stage at Newcastle's Metro Radio Arena in mini-dresses.
The Saturdays are currently on their 'Greatest Hits Tour' but, as it wraps up on 23 September, we're pretty sure Una will still be able to squeeze into them by then!
Pop star Una announced her pregnancy to fans on Instagram on Monday (8 September), saying: "I know lots of people have been guessing and Ben and I can now confirm that Aoife is going to have a baby brother or sister next year! We're all very happy!"
Following her message, The Saturdays were quick to send their public congratulations with Rochelle Humes even joking that the Saturdays Juniors were "forming nicely"!
Last night, after their gig in Newcastle, Una decided to have an early night while the rest of the band partied the night away.
We're not surprise. Put your feet up, love!
Celebrities who have announced pregnancies in 2014:
Copyright: WENN Lexie Appleby/Future Image/Bridow/Instagram